1. Field of the Invention
The invention relates to a paper machine for producing paper that can be gravure printed from a fibrous stock suspension.
2. Description of Background Information
EP 0 732 446 B1 discloses a calender for the two-sided treatment of a paper web, which is in particular also suitable for the production of paper that can be gravure printed. The calender comprises a roll stack which can be loaded from the end and has hard rolls and soft rolls as well as working nips in each case formed between a hard and a soft roll. In this case, some of the rolls can be heated. The stack has six to eight rolls having one roll nip formed by two soft rolls. Two identical stacks each having three or four rolls are provided.
The known calender is connected directly to a paper machine, from which the paper web is supplied. Then, under the guidance of guide rollers, the paper web runs through first working nips between rolls of the calender, a reversing nip, further working nips, and is then wound up into a wound roll. In the first working nips, the paper web rests with one side on the hard rolls and in the further working nips with the other side on the hard rolls, so that the desired surface structure, for example with regard to gloss or smoothness, is achieved on both sides.
In known paper machines, the gravure printing quality of a paper web has hitherto been achieved only by applying a coating color by a blade (blade coat). As a result of this form of application, the paper is loaded highly and, because of the high break tendency of the blade coat, the speed for the online production of the paper web from the fibrous stock suspension as far as a paper coil wound up on a roll is limited to 1400 to at most 1500 m per minute.